211990231 has 2 divisors, whose sum is σ = 211990232. Its totient is φ = 211990230.

The previous prime is 211990199. The next prime is 211990243. The reversal of 211990231 is 132099112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 211990231 - 2⁵ = 211990199 is a prime.

It is a super-2 number, since 2×211990231² = 89879716078866722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 211990231.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211990271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105995115 + 105995116.

It is an arithmetic number, because the mean of its divisors is an integer number (105995116).

Almost surely, 2^211990231 is an apocalyptic number.

211990231 is a deficient number, since it is larger than the sum of its proper divisors (1).

211990231 is an equidigital number, since it uses as much as digits as its factorization.

211990231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 211990231 is about 14559.8843058590. The cubic root of 211990231 is about 596.2640368399.

The spelling of 211990231 in words is "two hundred eleven million, nine hundred ninety thousand, two hundred thirty-one".